A trackhoe operator was cleaning out the bed of a Kenworth Tri-axle dump truck. The dump bed was raised and the trackhoe was scraping material out of the bed. The injured employee approached the dump truck while this was occurring and proceeded to stick his head in between the dump bed and the swing gate to see inside. The excavator made contact with the bed and caused the swing gate to move, catching the injured employee's head between the truck bed and the swing gate. He was admitted to the hospital with a fractured skull.